With increasingly higher degrees of integration and functionality of semiconductor integrated circuits in recent years, research on semiconductor devices having a multilayer interconnection layer in which wires are stacked in the vertical direction is under way.
The following method is known as a method for manufacturing a multilayer interconnection layer included in such a type of semiconductor devices. First, a first interconnection layer is formed on a first semiconductor substrate. The first interconnection layer has a surface polished by the CMP (Chemical Mechanical Polishing) method. In the surface, a conductive layer such as a wire or a through hole conductive material, and an insulating layer are exposed. Subsequently, a second interconnection layer is formed on a second semiconductor substrate. The second interconnection layer has a surface polished by the CMP method. In the surface, a conductive layer such as a wire or a through hole conductive material, and an insulating layer are exposed. Next, the surface of the first interconnection layer and the surface of the second interconnection layer are bonded as solid state bonding by applying a pressure welding load to the first semiconductor substrate and the second semiconductor substrate. In this manner, the multilayer interconnection layer is manufactured.
A semiconductor device including the multilayer interconnection layer manufactured as described above is manufactured by solid state bonding of the surface of the first interconnection layer and the surface of the second interconnection layer and therefore, electromagnetic radiation noise can easily be suppressed. Further, the semiconductor device including the multilayer interconnection layer manufactured as described above is manufactured by solid state bonding of through hole conductive materials and therefore, a wire can be made shorter and manufactured easily.
In the above manufacturing method of the semiconductor device, a manufacturing method capable of manufacturing a more reliable semiconductor device by reliably bonding a conductive layer exposed from the surface of the first interconnection layer and a conductive layer exposed from the surface of the second interconnection layer is desired.